Lift bridge



J. B. STRAUSS LIFT BRIDGE May 16, 1933.

Filed Aug. 30,- 1926 2 Sheets-Sheet 1 Patented May 16, 1933 UNITED STATES JOSEPH B. STRAUSS, OF CHICAGO, ILLINOIS I LIFT BRIDGE Application filed August 30, 1926. SerialNo. 132,382.

r This invention relates to improvements in lift bridges and has for its object to provide a new and improved device of this description. The invention has as a further object to eliminate the difficulties and objectionable features of lift bridges as hereto constructed where cables were used to lift and lower the main span. The invention has as another object to provide means for securing uniform and equal motion of the main span. The invention has as another object to provide means for properly balancing a lift bridge. The invention has further objects which are more particularly pointed out in the accompanying description.

Referring now to the drawings,

Fig. 1 is a side elevation of one form of bridge embodying the invention.

Fig. 2 is a plan view of the bridge illustrated in Fig. 1.

Fig. 3 is a view of one of the towers as seen from the line 33 of Fig. 1.

Fig. 4 is a view showing one of the racks and the .connection between the rack and the driving shaft of the main span.

Fig. 5 is a view showing the counterweight and the adjusting means therefor.

Fig. 6 is an enlarged side view of the counterweight. I

9 Fig. 7 is a plan view of the bridge showing a modified construction.

Fig. 8 is a view of one of the towers similar to Fig. 3, showing the modified construction of Fig. 7. g Y Fig. 9is a view showing one form of connection between the racks on the'towers and the driving pinion on the main span. Fig. 10 is an enlarged view in more detail showing the tower 2 of Figure 7 and the racks connected thereto.

Like numerals refer to like parts throughout-the several figures.

, Referring now to the drawings,- which showone form of the invention, I have illustrated the main span 1 adapted to be moved vertically to lift and lower it. Associated with the main span are the towers 2 and 2a along which the span is moved when it is lifted and lowere Connected with the towers are the racks reducing devices with the 1notor'6 and 6a.

3 and 8a. In the construction shown in Figures 1, 2 and 3 these racks are centrally located, as clearly set out in Figure 3. These racks are engaged by pinions 4 and etc connected with shafts 5 and 5a, which shafts are connected by a speed reducing mechanism or gears with motors 6 and 6a. In the par ticular' construction shown these shafts are provided with gears 7 and 7a which connect with pinions 8 and 8a, on the shafts 9 and 9a. These latter shafts are provided with gears 10 and 10a, which connect with pinions lland 11a on the shaft 12.

. This latter shaft is connected by speed It is of course evident that any desired speed reducing mechanism may be used. I

In Figure 4 I have illustrated a means for keeping the pinions in proper engagement with the rack. In this construction the rack is shown as an angular member and is provided with a projection 14:. A roller 15 connected with the main span engages this projection so as to hold the pinion in proper re-. lation with the teeth of the rack. The roller 15 is connected to the shaft 16 and is mounted in bearings on the main span. I prefer also to provide a roller 17 at the other side of the rack which engages the part 18 on'the rack. The roller 17 may be on the shaft 5.

' It will be noted that the main span is lifted and lowered by means of these pinions and racks. The main span is provided with suitable counterweights 19 and 19a. These counterweights are connected with the main span by flexible members 20 and 21, 20a and 2102. These flexible members run vertically upward adjacent the plane of one face of the associated tower and then past the direction changing devices 22, 23, 22a and 23a, and are then connected with the counterweights. The counterweights are adjacent the opposite faces of the tower as clearly shown in Figure land move in a plane adjacent to said opposite faces. The direction changing devices are located between the faces of the towers and are supported upon cross-girders 24, 25, 24a and '25a.-

It will be seen that as the counterweights 19 and 19a are moved, portions of the cables by which they are connected to the main span pass from one side of the direction changing devices to the other side thereof. When, for example, the main span is lowered substantially all of the weight of these cables is counterbalanced by the counter-weights. As the counterweights lower, portions of these cables pass to the other side of the di rection changing devices. This decreases the weight which is to be counterbalanced by the counterweights and in addition adds the counterbalancing effect of the portions of the cables between the counterweight and the direction changing devices. This produces an unbalanced condition and I provide compensating means so as to maintain the proper counterbalancing effect. In the construction shown I provide a series of compensating weights, the number of weights depending upon the length and weight of the cables and the degree of accuracy required.

I have shown a series 26 to 26a of these compensating weights which are connected with the main counterweights. At intervals along the towers are provided a series of carrying members 27 arranged to successive- 1y receive and hold these compensating weights as the main counterweight is lowered. For example, when the cables passing over the direction changing devices become equal to the weight of the compensating weights 26 and 2679, these weights are removed by the associated parts 27 and hence the weight of the counterweight plus the weight of the cables at this point is the same as the original weight of the counterweight.

As the counterweight continues to lower, the other compensating weights 26a, 26% and 26?), 26722, etc. are successively removed and the weight of the cables which is added to the counterweight thereby compensated for, so as to maintain a substantially uniform weight of the counterweight with relation to the weight which it is to counterbalance. In order to prevent unbalanced strains I have shown the compensating weights as being removed, two at a time, the two removed each time at opposite sides of the center of gravity of the counterweight a substantially equal distance therefrom. It is of course evident that any other arrangement of the compensating weights than that herein shown may be used.

When the bridge is lowered and the counterweights lifted, the cables pass over the direction changing devices from the side of the counterweight to the side of the main span thereby decreasing the counterweight effect of the counterweight on the main span. To compensate for this change in the counterweight effect, the counterweights in their upward movement successively remove the compensating weights 26, 2612, and 26a, 26%, etc. from their supports 27 so that their counterweight effect is added to the counter- Weights, thereby making the counterweight effect of the counterweights substantially equal to the weights which they are to counterbalance.

It will therefore be seen that there is here means for automatically compensating for the change of the cables from one side to the other of the direction changing devices. That is to say, for compensating for the unbalancing effect produced by the cables as the bridge is raised or lowered. The current for the electric motors is taken from conductors 28, 29, 30 (see Fig. 4) which extends vertically along the tower by the brushes 31, 32, 33 carried by the support 84 on the main span. These brushes are connected by conductors 35, 36, 37 with the motors. In Figs. 7, 8, 9, I have shown a modified construction wherein the towers 2 and 2a instead of having a central rack are each provided with two racks, one at each side thereof.

The tower 2 has the racks 38, 39, and the tower 2a has the racks 4:0, 41. The motors 42 and are connected by speed reducing mechanism with the shaft 45. This shaft is provided at its ends with the-pinions 46, 46a which engage gears 47, 470 on the shafts 48, 48a. The shaft 48 is provided with pinions 4-9, 50 which engage the gears 51 and'52 on the shafts 53 and 54c. The shaft 54 is provided with a pinion 55 which engages the rack 39. The shaft 53 has the pinion 56 which engages the rack 38. The shaft 48a is provided with the pinions 49a and 50a which engage the gears 51a and 52a on the shafts 53a and 54a. The shaft 54a has a pinion 55a which engages the rack 40 on the tower 2a and the shaft 53a has a pinion 56a which engages the rack 41 on the tower 2a. Associated with each rack, 38 etc. is a roller '57 (see Fig. 9) which engages a rack on the side opposite to that engaged by the pinion. These rollers 57 are connected with the shafts with which the associated pinions are connected and prevent the displacement of the pinions.

It will be noted that the towers are of relatively narrow width, each having an inner and outer face indicated by the reference characters 58 and 59 respectively, formed by structural elements 58a and 59a, spaced apart by end faces 60 and'61 respectively formed by structural elements 60a all as clearly shown in Fig. 10 so as to form hollow towers, the counterweights being located in the hollow towers. It will further be noted that the counterweight cables for the counterweights are connected with the span and that each cable then runs vertically upward adjacent the plane of its tower and over the sheave at the top of the tower and then downwardly connecting with its associated counterweight, and that the counterweights move in a part plane adjacent the opposite face of the tower and are contained within the tower. The

towers are provided with the ornamental tops 60 and 60a.

As a precautions measure I provide an internal combustion engine 13 which is'arranged to be connected with shaft 12 so that if the electric system fails to work for any reason, the bridge can still be raised and lowered. In Fig. 7 I have shown a similar internal combustion engine 44 adapted to be connected with the shaft 45.

The motors 6 and 6a and the engine 13 are inclosed in the housing 13a.

The toothed sections of the racks are connected with structural steel supporting members on the towers. One of these structural steel supporting members is illustrated in detail in the enlarged view of Fig. 9. The racks have teeth only on one side and the guiding device on the other side may be a roller which simply engages a flat surface.

There are structural steel supporting members on the towers for supporting the racks. This is most clearly shown in Figs. 8, 9 and 10. The racks 38 are at the corners. These racks are connected to structural steel supporting members consisting of the angle members 38a and 38?) connected together by the members 380 and 38d (see Fig. 9). The structural steel members 38a, 38b, 38c and 38d illustrated in Fig. 9 form the corners of the tower, that'is the two corners on the sides of the towers facing each other, and the racks are connected to them as shown in Fig. 10.

I claim:

1. A bridge comprising a vertically moving span, towers at the ends thereof, counterweighting mechanism for said span, flexible connecting devices connecting the counter weight mechanism with the span, a single, centrally located rack rigidly connected with each tower, pinions carried by the span and engaging said racks, and a motor on the span for operating said pinions to lift and lower said span.

2. A bridge comprising a vertically moving span, towers at the ends thereof, counterweighting mechanism for saidspa-n flexible connecting devices connecting the counterweight mechanism with the span, a single, centrally located rack rigidly connected with each tower, pinions carried by the span and engaging said racks, a motor on the span for operating said pinions to lift and lower said span and means for automatically varying the weight of the counterweighting mechanism as the span is raised and lowered.

3. A bridge comprising a vertically moving span, towers at the ends thereof, racks connected with said towers, pinions carried by the span and engaging said racks, means for rotating said pinions, a main counterweight associated with each tower, a flexible connecting device connecting each counterweight with the span, direction changing devices connected with the towers over which said flexible connected devices pass, a. plurality of independent compensating weights associated with each counterweight and substantially in the same horizontal plane when in position on said main counterweight and means for removing and replacing said weights as the span is raised and lowered.

4. A bridge comprising a vertically moving span, two towers, acounterweighting mechanism comprising counterweights, cables connected thereto and to the span and an operating mechanism comprising fixed racks on the towers and pinions on the span, means for rotating the pinions to lift and lower the span structural steel supporting members on the towers and made up of a series of separated members fastened together and built. into and forming the corners of the towers and separate toothed sections connected thereto to form the racks.

5. A bridge comprising a vertically moving span, a single tower in each end of the span, a counterweighting mechanism comprising counterweights, cables connected thereto and to the span and an operating mechanism comprising a single rack rigidly fastened near the middle of each tower and pinions on the span, means for rotating the pinions to lift and lower the span structural steel supporting members on the towers and made up of a series of separated members fastened together and built into and forming the corners of the towers and separate toothed sections connected thereto to for-m the racks, guiding devices associated with I the span and engaging the racks to align the span while moving.

6. A bridge comprising a vertically moving span, a single tower'on each end of the span, a counterweighting mechanism comprising counterweights, cables connected thereto and to the span and an operating mechanism comprising a single rack rigidly fastened near the middle of each tower and pinions on the span, means for rotating the pinions to lift and lower the span, a motor for operating said pinions, structural steel supporting member on the towers and made up of a series of separated members fastened together and built into and forming the corners of the towers and separate toothed sections connected thereto to form the racks, guiding devices associated with the span and engaging the racks to align the V span while moving electrical conductors extending along the towers and electrical contact devices carried by the vertically moving span whereby current may be supplied to the span in any position.

7. A bridge comprising a span, a main counterweight for said span, a support for said counterweight, said counterweight moving along said support, separate sections resting on the top of said counterweight and arranged side by side thereon when the span is closed and independent of each other and means for automatically lifting said sections off and replacing them on said counter- Weight.

8. A bridge comprising a vertically moving span, a main counterweight, a tower along which said counterweight moves, separate counterweight sections normally supported side by side on said counterweight and members on the tower engaging said separate counterweight sections as the counterweight moves down and up whereby said counterweight sections are removed from and replaced on said counterweight to vary thecounterweights effect thereof.

Signed at Chicago county of Cook and State of Illinois, this 21st day of August 1926.

JOSEPH B. STRAUSS. 

